Yesterday's play at the Australian Open was littered with high-profile casualties as two of the men's favourites, Pete Sampras and Marat Safin, were sent home early in major fourth round upsets.

Sampras, bidding to extend his record-breaking haul of 13 Grand Slam titles, looked on track when he edged a first set tie-break against compatriot Todd Martin. But from then on, Martin's serve and return were irresistible as he completed a 6-7 (2/7), 6-3, 6-4, 6-4 win that was only his third in 20 matches against Sampras.

Martin now faces Andre Agassi, who beat Australian Andrew Ilie earlier in the day, in the quarterfinals. With Sampras, Safin and world number one Gustavo Kuerten all out, Agassi is now odds-on favourite to claim his third Open title. Safin's conqueror, Dominik Hrbaty, will meet Australia's Pat Rafter, who beat Tim Henman in straight sets, in the other quarterfinal in the top half of the draw.

Despite the defeat and a growing sense that his best days are behind him, Sampras insisted retirement was not an issue. "I feel like I can still win majors and I want to win a few more before I am done," he said. "I'm disappointed not to have done it here but I've got many years and many slams ahead of me."

Agassi tamed showman Ilie in four sets to book his place in the last eight. Ilie, who has delighted the home crowd with his shirt-ripping antics, looked briefly like he could pull off his biggest ever victory. The Romanian-born player produced a string of winners to sweep the first set tie-break and then broke Agassi in the third game of the second. But the Las Vegan broke back immediately and soon took control.

Rafter looked close to his best as he dismissed Henman in straight sets. The British number one was left in no doubt that Rafter was playing well enough to add the first Grand Slam of the year to his two US Open titles.

"No question that was the best he's played against me," Henman said. "I've watched quite a lot of his matches and you've been able to see a marked improvement with each one. I'm sure he will feel very good about his chances." Rafter, who won 6-2, 6-3, 6-3, said: "I have been hitting the ball pretty well, but that was something exceptional for me today." So satisfied was the Australian at reaching the quarter-finals of his home grand slam for the first time that he walked back into the Rod Laver Arena and attempted to rip his shirt apart, mimicking the victory celebration of his compatriot Ilie, who had earlier lost to Agassi.

Rafter cut the collar with a knife but was unable to rip it off his chest despite vigorously yanking and tearing at it and stretching it over his knee. In the end he removed the shirt and tossed it into the crowd.

In the women's singles, fourtime champion Monica Seles found herself in a three-set dogfight and had to claw back from the brink twice against rising teenage star Justine Henin. The veteran campaigner, though, is made of stern stuff and joined Lindsay Davenport, Jennifer Capriati and Anna Kournikova in the quarterfinals. Davenport plays Kournikova, who is in a Grand Slam last eight for only he second time.

Seles pulled back from one set down and 2-4 in the second and third sets against the spirited Henin, drawing on her experience to win 4-6, 6-4, 6-4. "I think coming into this tournament Justine has been playing better tennis with her confidence high, winning two tournaments," she said and pointed to her fighting spirit as the asset that finally won the day.

Davenport will next play Kournikova, who is into a Grand Slam quarter-final for the first time since making the semi-finals at Wimbledon in 1997. The Russian, who beat Germany's unseeded Barbara Rittner 6-3, 6-1, said she was confident of her chances against the defending champion.

"I have a good record against Lindsay, I have beaten her a few times," she said. "I'm not playing my best for sure right now but I will go out there and try to play and fight as much as I can."

Davenport beat Kournikova in the fourth round here last year, but the 18-year-old has the advantage of knowing she won their last encounter - in San Diego in August.